Cefpodoxime proxetil (CFP), an oral third-generation cephalosporin, is a
prodrug that is de-esterified in vivo to its active metabolite, cefpodoxime acid
(CFA). Therefore, this study aimed to develop a facile and efficient one-pot
reaction for selective and sensitive determination of CFA and its prodrug (CFP).
The method was based on single-step reaction between CFP or CFA and 1,2-
naphthoquinone-4-sulfonate (NQS) as a selective derivatizing reagent in alkaline
medium without heating, extraction or reduction steps as usual for NQS
derivatization reactions. The fluorescence of the formed NQS-derivative was
monitored directly at emission wavelength of 440 nm after excitation at 330 nm.
The method can easily be implemented in plating facilities by operators and/or
incorporated in on-line derivatization reaction. The correlation coefficients of
0.9991 and 0.9984 were obtained in the concentration ranges of 50–2000 ng
mL−1 for CFA and CFP, respectively. The detection limits were 9.17 and 9.48 ng
mL−1 for CFA and CFP, respectively. The method was validated in accordance
with the requirements of ICH guidelines and shown to be suitable for their
efficient and sensitive determinations. The developed method was successfully
-2-
applied for selective determination of CFP in pure form and in pharmaceutical
dosage forms as well as CFA in human urine after single dose of CFP without
prior need for separation. The method is valuable for quality control laboratories
for monitoring of CFP and its active metabolite CFA.